YUMA, Ariz. - President Bush boasted of tougher enforcement along the Mexican border Monday as he tried to revive his stalled efforts to overhaul U.S. immigration laws. Many of his fellow Republicans in Congress are opposing him.

Frustrated by his failure to get a bill approved last year when the GOP was in charge, Bush said prospects look brighter in the Democratic Congress. "I think the atmosphere up there is good right now," he said.

His message - particularly to conservative critics from his own party - was that stepped-up border enforcement is working and it's time to adopt a temporary worker program, hold U.S. employers accountable for the workers they hire and resolve the status of the millions of illegal immigrants already in the United States.

He saluted the opening of a new border patrol station in this southwest corner of Arizona and said, "This border is more secure and America is safer as a result."

The president was joined by Sen. Jon Kyl, the Arizona Republican whose support is crucial to any deal in the Congress. Another lawmaker vital to Bush's effort, Democratic Sen. Edward M. Kennedy of Massachusetts, issued a statement that said: "President Bush did the right thing today by speaking out."

"Only a bipartisan bill will become law," Kennedy said. "There is a lot of common ground, especially in the need to strengthen our borders and enforce our laws, though important differences remain to be resolved."

Administration officials led by Homeland Security Secretary Michael Chertoff and Commerce Secretary Carlos Gutierrez have been meeting privately for weeks with Republican senators in search of compromise. That expanded to a meeting in late March with key senators from both parties. The administration floated a proposal that would make it harder for millions of illegal immigrants to gain citizenship than under legislation passed by the Senate last year.

Bush stopped here on the way back to Washington from an Easter holiday at his Texas ranch. He climbed in the back of a pickup truck at a National Guard observation post to see how a portable scope tracks people charging across the border at night. Then, his motorcade barreled along a rocky, dusty road between two new walls of fencing protecting the U.S. border.

Bush watched a rig plow holes in the ground to prepare for more fencing, steel-winged at the bottom to make it harder for illegal immigrants to tunnel underneath it.

Contending that tougher enforcement is paying off, Bush said: "The number of people apprehended for illegally crossing our southern border is down by nearly 30 percent this year. We're making progress." Sharply at odds over the war in Iraq, Bush and the Democratic Congress are eager to show some accomplishment on a core issue like immigration. Less than two years from leaving office, Bush is losing clout as attention turns to the presidential election in 2008. The compromise immigration plan that was floated last month was described as a draft White House proposal by officials in both parties and advocacy groups who got copies of the detailed blueprint. The White House disputes that characterization. Spokesman Scott Stanzel said it was only a starting point, an emerging consensus of Republican senators and the White House. Regardless, the proposal has already met opposition. Thousands of people marched through Los Angeles on Saturday, spurred in part by what they called a betrayal by Bush. The plan would grant work visas to undocumented immigrants but require them to return home and pay hefty fines to become legal U.S. residents. They could apply for three-year work visas, dubbed "Z" visas, which would be renewable indefinitely but cost $3,500 each time. The undocumented workers would have legal status with the visas, but to become legal permanent residents with a green card, they'd have to return to their home country, apply at a U.S. Embassy or consulate to re-enter legally and pay a $10,000 fine. So far, Bush has only gotten part of what he wants - border legislation. He signed a bill last October authorizing 700 additional miles of fencing along the U.S.-Mexico border. AP-CS-04-09-07 1656EDT